The invention relates to a magnetic apparatus, more particularly to an elevation apparatus having a soft landing mechanism for landing the head on the recording medium, a reference position detection mechanism and a carriage mechanism for moving the magnetic head.
FIG. 6, FIG. 7, FIG. 8 and FIG. 9 show a conventional elevation apparatus as taught in the laid-open Japanese patent publication No. 2-152075.
In the figures, a head carriage 1 comprises a lower mounting portion 2 and an arm mounting portion 3 which are clamped by a screw 4 and a nut 5. A guide groove 6 is formed on a lower protruding portion of the lower mounting portion 2. A guide rod ( not shown) is inserted in the guide groove 6. The head carriage 1 is guided by the guide rod and able to move in the radial direction of a disk 7.
A head arm 8 comprises an upper head mounting portion and a blade spring 10. At one side of the blade spring 10, an upper mounting portion 9 is fixed. At another side of the blade spring 10 is fixed the arm mounting portion 3. The head arm 8 is supported by the blade spring 10 so that it is able to rotate against the head carriage 1. An upper head 11 and a lower head 12 are mounted at opposing positions on the upper mounting portion 9 and the lower mounting portion 2, respectively. The upper head 11 is able to move up and down by the curving of the blade spring 10. At the down position of the upper mounting portion 9, the upper head 11 and the lower head 12 contact both the surfaces of the disk 7, where the recording medium is at the state of being able to be read and written to. At the up position of the upper mounting portion 9, the upper head 11 and the lower head 12 are removing from both the surfaces of the disk 7, where the disk 7 may move between the two dot chain line showing the disk insertion position and the solid line showing the disk mounting position.
As shown in FIG. 8, a damper mechanism 13 comprises a slide room 14 opening on the upper side of the upper head mounting portion 9 and a slider 15 arranged so as to move freely in the slide room 14. The high viscosity agent such as silicon grease is filled between the slider 15 and the slider room 14. On the slider 15, a groove 16 is formed for inserting an end of a torsion coil spring 17. The torsion coil spring 17 is supported at a spring holding portion 18 of the arm mounting portion 3. The head arm 8 is moved downwards by the spring force of the torsion coil spring 17. That is, the torsion coil spring 17 is a connection member for connecting the slider 15 with the arm mounting portion 3 as well as the moving mechanism for moving the head arm 8 downwards. The blade spring holding portion 18 is arranged at a different position from the other end of the blade spring 10 which is the rotation supporting point of the head. The slider 15 slides in the slide room 14 for a predetermined distance during the rotation of the head arm 8.
As shown in FIG. 9, two protruding walls 20 are formed in the slide room 14 in the sliding direction. In the slider, two grooves 21 are formed corresponding to the protruding walls 21. Two holder engaging portions 22 are protruding at both sides of the upper head mounting portion 9 and engage the disk holder (not shown in the figure). The disk holder goes up and down between the inserting position and the mounting position of the disk. When the disk is at the inserting position, the holder engaging portion 22 contacts on the upper surface of the disk holder, and the head arm 8 is located at the upper position as shown in FIG. 6. When the disk is at the mounting position, the holder engaging portion 22 removes from the upper surface of the disk holder, and the head arm 8 is located at the lower position by the force of the torsion coil spring 17 as shown in FIG. 7.
The operation of the conventional disk apparatus is explained here. When the disk holder is in the disk inserting position and the head arm 8 is in the upper position, if the disk 7 is inserted into the disk holder, the disk holder immediately moves to the disk mounting position from the two dot chain line to the solid line as shown in FIG. 6. The holder engaging portion 22 removes from the upper surface of the disk holder and the head arm 8 rotates downwards.
The slider 15 slides in the sliding room 14 against the resistance of the high viscosity agent along with the rotation of the head arm 8. Since the slider 15 slides against the resistance of the high viscosity agent, the head arm 8 also rotates downward in response to the slider 15 and the upper head 11 lands slowly on the upper surface of the disk 7.
The duration Td (called "head landing time" below) during which the head arm 8 moves from the upper position to the upper surface of the disk 7 and the upper head 11 moves to the landing position must be within a predetermined time.
As the conventional head elevation apparatus is constructed described above, the head landing time Td becomes unstable because it is decided by the viscosity resistance applied to the slider 15 and the spring force such as the torsion coil spring 17 which rotates the head arm 8 downwards. Accordingly, it is difficult to obtain a desired head landing time Td. This is because the viscosity resistance and the spring force cannot be set independently. In this construction, the viscosity resistance is proportional to the spring force such as a torsion coil spring 17 which compresses the high viscosity agent between the sliding room 14 and the slider 15. Since the viscosity resistance and the spring force acting on the head arm 8 cannot be set independently, the upper head 11 sometimes cannot contact the disk 7 with a desired contact force. As a result, it is difficult to record or reproduce the data correctly.
When the head arm 8 rotates downwards, the slider 15 sometimes removes from the sliding room 14. In that case, the viscosity resistance does not act well on the slider 15 and also the upper head 11 does not land slowly on the disk 7. Further, since the damper mechanism is mounted in the head arm 8, it has been difficult to make the head arm 8 thin and also to make the disk apparatus thin.
Optical sensors are sometimes used as means for detecting the position of the reference track (the outerest track 00 is generally referred as a reference track in the magnetic disk apparatus). FIG. 17 is a plan view of one of the example of the track 00 position detecting mechanism in the magnetic apparatus disclosed in the laid-open Japanese patent publication No. 3-71459.
In the figure, 701 is a magnetic medium for storing the data. 702 is a magnetic head for recording or reproducing the data on the magnetic medium 701. 703 is a head carriage for holding the magnetic head 702. 704 is a head driving motor for reciprocating the head carriage 703 to the target track in the radial direction on the magnetic medium 701. 705 is a lead screw for converting the driving torque of the head driving motor 704 to driving force toward the linear direction of the head carriage 703. 706 is a guide rod for guiding the head carriage 703 toward the radial direction on the magnetic medium 701. 707 is a torsion coil spring 17 for applying force to the head carriage 703 so as to cause the magnetic head 702 to contact with the magnetic medium 701.
708 is a track sensor for detecting the track position 00 by an optical sensor. 709 is a light shielding flag which protrudes perpendicular from the head carriage 703 outward and moves toward the track sensor 708 in order to shield the light. 710 is a sensor mounting board for mounting the optical sensor 708. 710a is a positioning long hole for adjusting position of the sensor mounting board 710. 711 is a positioning pin. 712 is a screw for fixing the sensor mounting board 710 after adjusting it. 713 is an assembling screw for assembling the head carriage 703. 714 is a frame for assembling the head driving motor 704.
FIG. 18 is a side view showing the positional relation between the track sensor 708 for detecting position of the track 00 and the shielding flag 709 which protrudes from the portion of the head carriage 703. 715 is a light emitting element. 716 is a receiving element for converting the received light to a voltage.
The operation of the conventional apparatus is explained here. In FIG. 17, the head carriage 703 holding the magnetic head 702 is assembled by the assembling screws 713. The head carriage 703 forced by the torsion coil spring 707 and makes the magnetic head 702 contact the magnetic medium 701 so as to read and write the data. The head carriage 703 is connected by the lead screw 705 which is connected to the driving motor 704. The rotating motion of the head driving motor 704 is converted to the linear motion where the head carriage 703 moves. The head carriage 703 moves reciprocally toward the radial direction for the concentric circle of the track formed on the magnetic medium 701.
In order for the magnetic head 702 to read and write precisely the data on the target track, it is necessary to position the head by controlling the distance from the reference track 00 at the most outer circle. Therefore if the reference track 00 is not detected precisely, the data cannot be read and written correctly. In such a case, the reliability of the magnetic disk is lost. For avoiding this disadvantage, the optical track sensor 708 comprises the light emitting element 715 and the receiving element 716 which are arranged at the opposite side of its concave portion as shown in FIG. 17. The light shielding flag 709 which moves together with the head carriage 703 is inserted horizontally between the light emitting element 715 and the receiving element 716 so as to detect the track 00.
The end surface of the light shielding flag 709 is parallel to the moving direction of the head carriage 703. The light shielding flag 709 cuts or passes the light from the light emitting element 715 and an output voltage is generated in accordance with the light quantity received in the receiving element 716. If the track sensor 708 is mounted without adjusting its location, the light shielding flag 709, which moves together with the head carriage 703, relatively drifts from the optical sensor 708 by the influences such as the element tolerance and the assembling error. Therefore, it is difficult to correctly position the track sensor 708. Accordingly, it is necessary to adjust the track sensor 708 toward x direction which is the same moving direction of the head carriage 703. The track sensor 708 is adjusted as follows. The track sensor 708 is mounted on the sensor mounting board 710 and then the track sensor 708 is moved toward x direction so that the positioning long hole 710a moves along with the positioning pin 711 which is protruding from the frame 714. When the output voltage of the optical sensor 708 reaches to the target voltage, the adjusting is finished to decide the point to be a track 00 and the mounting screw is fixed to the frame 714.
Since the conventional reference track detection mechanism is constructed as described above, when adjusting the track sensor, adjusting the range toward the carriage movement influences directly the depth dimension. That is, the reference track position detection mechanism of the conventional magnetic apparatus needs to ensure the adjusting distance at the back of the head carriage. Accordingly it is difficult to make the depth dimension short and to make the apparatus small in size.
FIG. 31 is a perspective view of a conventional flexible magnetic disk apparatus (FDD) disclosed in the laid-open Japanese patent publication No. 63-225966. FIG. 32.about.FIG. 33 are brief sectional views of FIG. 31. In the figures, 601 is an assembled body (disk jacket) comprised of a disk, a jacket case having a window for recording and reproducing the data and a shatter for opening or closing the window. 602 is an FDD. 603 is a spindle motor for rotating the disk mounted on the disk mounting surface 603a. 603b is a spindle shaft protruding from the center of the spindle motor 603 higher than the disk mounting surface 603a for positioning the disk. 604 is an S0 head, 605 is an S1 head. 606 is a carriage for holding the S0 head 604. 607 is an S1 arm mounting the S1 head 605 at its one end for rotating against the carriage 606. The other end of the S1 arm 607 is mounted at the carriage 606 via a blade spring 608.
In the conventional FDD 2, the diskette 601 is inserted horizontally against the disk mounting surface 603a of the spindle motor 603 and then mounted to the spindle motor 603.
Since the conventional FDD is constructed as described above, it is difficult to make the apparatus thin. The reason is explained using FIG. 33 below. When the diskette 601 is inserted horizontally against the disk mounting surface 603a, the insersionable height is H1 which is the distance between the apex of the spindle shaft 603b and the lower end of the S1 head 605. When the diskette 601 is inserted obliquely with the angle .THETA. against the disk mounting surface 603a, the insersionable height is H2 as shown in FIG. 33. The relation between H1 and H2 becomes H1&lt;H2, therefore it is easily understood that inserting the diskette 601 obliquely into FDD has a height advantage over inserting the diskette 601 horizontally. When the diskette 601 is inserted with the angle .THETA. into FDD, the height of the FDD becomes thinner by about H.multidot.2 cos .THETA.-H1.
Although it is able to make the apparatus thinner if the diskette 601 is inserted obliquely against the disk mounting surface 603a, the diskette 601 crushes the S0 head 604 as shown in FIG. 34. Since the conventional apparatus has no soft landing mechanism in which the S1 head 606 lands slowly on the disk, the head is apt to give a flaw to the disk and head.
It is an object of the present invention to obtain stable landing time Td.
It is also an object of the present invention to provide a soft landing mechanism which gives a desired contact force between the upper head and the disk for obtaining a thin type magnetic disk apparatus.
It is a further object of the present invention to provide a short depth dimension and a small size apparatus and also to provide a mechanism for easily adjusting the apparatus.
It is still a further object of the present invention to provide a safety carriage mechanism in which the diskette does not crash to the S0 head if the diskette is inserted obliquely against the disk mounting surface of the spindle motor.
It is more over an object of the present invention to provide a carriage mechanism having a soft landing mechanism in which a head lands slowly on the disk.